This invention relates to a wall box seal for the slag blower or lance tube of a device employed for blowing soot or other combustion products from the tubes of boilers.
Customarily, a plurality of wall box seals are mounted on the side wall of a boiler with the rotatable and projectable tubular slag blower or cleaning element extending therethrough and into the combustion chamber adjacent the boiler tubes to be cleaned. The wall box seals are provided for the purpose of preventing products of combustion and soot from escaping from the interior of the boiler to the exterior thereof along the outer surface of the tubular slag blower as it rotates and reciprocates and conveys fluid under pressure to nozzles or outlet openings in the slag blower at the head end thereof.
The tubular slag blower member, through which steam, air or some other suitable cleaning material is forced under pressure for blowing the boiler tubes clean, usually becomes warped due to the heat of the furnace and roughened and worn on its outer surface where it slides and rotates through the wall box seal. The seal also becomes worn and must frequently be replaced or repaired in order to prevent the escape from the boiler interior of soot and combustion products which present health hazards to persons in the area adjacent the boiler.